<body>
<div id="app">
</div>
<script type="text/babel">
class Dollar extends React.Component{
constructor(props) {
super(props);
this.handleChange = this.handleChange.bind(this);
}
handleChange(event) {
this.props.dollarChange(event.target.value); //将子组件的值通过props传给父组件
}
render() {
const money = this.props.money;
const yuan = this.props.yuan;
const text = this.props.type == 'd' ? '美元' : '人民币';
return <fieldset>
<legend>{text}</legend>
<input value={money} onChange={this.handleChange}/>
</fieldset>
}
}
class Box extends React.Component{
constructor(props){
super(props);
this.state = {
dollar: '',
yuan: '',
};
this.dollarInput = this.dollarInput.bind(this);
this.yuanInput = this.yuanInput.bind(this);
}
dollarInput(value) {
if (parseFloat(value) || value == '' || parseFloat(value) == 0) {
this.setState({
dollar: value,
yuan: value == '' ? '' : value * 6.9977
});
} else {
alert('输入值必须为数字。');
}
}
yuanInput(value) {
if (parseFloat(value) || value == '' || parseFloat(value) == 0) {
this.setState({
dollar: value == '' ? '' : value * 0.1429,
yuan: value,
});
} else {
alert('输入值必须为数字。');
}
}
render() {
return <div>
<Dollar type = {'d'} dollarChange = {this.dollarInput} money = {this.state.dollar}/>
<Dollar type = {'y'} dollarChange = {this.yuanInput} money = {this.state.yuan}/>
</div>
}
}
ReactDOM.render(
<Box />,
document.getElementById('app')
);
</script>
</body>
